1) Field of the Invention
The present invention relates to an apparatus and method for disposing conduits, wires, and the like through structures, for example, in connection with the placement of electrical wires through a wall to an outlet or switch.
2) Description of Related Art
The wires of an electrical system for a building structure are typically housed in tubular conduits. The tubular conduits can extend through walls, attics, basements, and crawlspaces, between floors and ceilings, and the like. In order to position the tubular conduits in an existing building, such as during a retrofitting of the electrical system of the building, the conduits are often inserted through the structure via a limited number of access points.
For example, in one typical installation, flexible metal conduit is inserted at the top of a wall to extend between the two parallel faces of the wall down to an electrical outlet or switch positioned on the wall. In order to install the conduit in this configuration, a long electrical snake or guide line is fished between the two access points. For example, a first end of the guide line can be inserted into a hole in the wall at the location of the outlet or switch and pushed in a direction toward the top of the wall until the first end emerges from the top of the wall. Importantly, the guide line is long enough to extend entirely through the wall with at least an equal length of the guide line disposed outside the wall. Thus, with the guide line positioned in the wall, the first end of the guide line can be inserted through a first end of the conduit, completely through the conduit, and out of a second end of the conduit. The first end of the guide line is hooked onto the conduit. The guide line is then pulled back through the wall by its second end so that the first end of the guide line, which now trails at the end of the guide line, pushes the conduit into position, i.e., between the two access points. The guide line, which is still disposed in the conduit, can be unhooked from the conduit and instead hooked to a wire or pull string so that the wire or pull string is pulled into the conduit as the guide line is removed therefrom. If a pull string is used, the pull string can then be connected to a wire and used to pull the wire into the conduit.
As the guide line and conduit are pulled through the wall, because the first end of the guide line is hooked to the back (i.e., the trailing end) of the conduit, it pushes the conduit and, in some cases, compresses and reduces the length of the conduit. For example, conduit formed of corrugated metal tubing can be compressed and shortened by 25% of more during installation. Thus, in some cases, the conduit must be provided with a length that is about ⅓ longer than the distance between the access points so that the conduit reaches between the access points after it is compressed during installation. This generally requires a greater amount of conduit for a given installation. In addition, the conventional installation requires separate operations for installing the conduit and the wiring. That is, as described above, the conduit is first positioned in the structure between the two access points, and then the guide line or a pull string is used to pull the wire into the conduit.
Thus, there exists a need for a device and method for installing tubular conduit, wire, and the like in a structure. The device should be capable of connecting a snake or guide line to the conduit so that the conduit can be pulled into position without significant compression of the conduit. Further, the device should be capable of connecting to the conduit and/or the wire without the guide device being disposed through the entire conduit.